← Add and subtract 3-digit numbers left to right lesson New set →

3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 241 · 40 questions
TalentJR

How to do it in your head (Hundreds first): Keep the first number as it is and split the second into hundreds, tens and ones. Add (or take away) the hundreds first, then the tens. Finish with the ones — bridge through a ten if you need to.

NameDateTime takenScore ___ / 40
  1. 1.575 − 303 =
  2. 2.178 + 233 =
  3. 3.580 + 202 =
  4. 4.423 − 316 =
  5. 5.599 + 399 =
  6. 6.460 − 139 =
  7. 7.828 − 176 =
  8. 8.834 − 535 =
  9. 9.560 − 162 =
  10. 10.614 − 119 =
  11. 11.304 + 414 =
  12. 12.264 + 642 =
  13. 13.412 + 559 =
  14. 14.519 + 128 =
  15. 15.594 − 254 =
  16. 16.553 − 372 =
  17. 17.480 − 288 =
  18. 18.720 − 395 =
  19. 19.644 + 433 =
  20. 20.647 − 545 =
  21. 21.621 − 126 =
  22. 22.974 − 186 =
  23. 23.545 + 197 =
  24. 24.172 + 661 =
  25. 25.694 − 441 =
  26. 26.320 + 547 =
  27. 27.633 + 687 =
  28. 28.625 − 422 =
  29. 29.180 + 451 =
  30. 30.471 + 318 =
  31. 31.463 − 352 =
  32. 32.774 − 607 =
  33. 33.964 − 738 =
  34. 34.782 + 563 =
  35. 35.865 − 469 =
  36. 36.519 − 331 =
  37. 37.579 − 192 =
  38. 38.455 − 291 =
  39. 39.482 + 635 =
  40. 40.418 − 174 =

Answer key

  1. 272
  2. 411
  3. 782
  4. 107
  5. 998
  6. 321
  7. 652
  8. 299
  9. 398
  10. 495
  11. 718
  12. 906
  13. 971
  14. 647
  15. 340
  16. 181
  17. 192
  18. 325
  19. 1077
  20. 102
  21. 495
  22. 788
  23. 742
  24. 833
  25. 253
  26. 867
  27. 1320
  28. 203
  29. 631
  30. 789
  31. 111
  32. 167
  33. 226
  34. 1345
  35. 396
  36. 188
  37. 387
  38. 164
  39. 1117
  40. 244

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths